In the commercial preparation of isotactic polypropylene using Ziegler-type catalysts, a significant by-product is atactic polypropylene. This atactic polypropylene is recovered in substantial quantities in the purification of the principal product, isotactic polypropylene. As recovered, the atactic polypropylene contains significant, say, up to about 10% by weight, of inorganic catalyst residues. This contaminated product is of no value and is currently discarded in a landfill. If the inorganics could be removed from the atactic polypropylene stream, the purified product could command a premium price in the adhesives market for example.
Alpha-hydroxysulfonic acids have been disclosed in the literature (see for example U.S. Pat. No. 3,248,278 issued Apr. 26, 1966 and U.S. Pat. No. 4,113,842 issued Sept. 12, 1978) for use in the removal of metal ions from aqueous metal streams. The process of the instant invention uses alpha-hydroxysulfonic acids for the removal of ionic residues from non-aqueous systems.